Electrical Isolation Device Capable Of Limiting Magnetic Saturation Even Upon Receipt Of High Power DC Bias And Method For Making The Same

ABSTRACT

An electrical device is produced by winding wires around a core. The device may be used as a transformer. Wires are inserted into, through and around a first hole and a first side of a core a desired number of times. Thereafter, the wires are extended along either a top or a bottom of the core and then passed through and around a second hole of the core. After the wires are wound around the second hole of the core and a second side of the core, the production of the device is complete.

BACKGROUND OF THE INVENTION

The connector industry is moving towards an environment where virtuallyany device maybe powered over a network using an ethernet cable.Previously, such power requirements reached as high as 15 watts. Nowstandards are requiring that ethernet cables and correspondingconnectors handle as much as 30 watts. In a typical RJ45 type connectorassembly where a modular plug mates in a male-female relationship with ajack, an isolating magnetic device is used in the connector to handledirect current (“DC”) offsets. Such offsets may be caused by variousfactors including imbalances in the wires of the plug.

For example, data is frequently transmitted over a pair of conductivewires. When transmitting data, the pair of wires may ideally havevoltage potentials to ground such that a voltage in one wire of the pairis equal and opposite to the voltage in the other wire of the pair. Forexample, one wire may have a potential of −2.5 volts and the other wiremay have a potential of +2.5 volts. I there are imbalances in the pairof wires or extraneous electro-magnetic interference, the two wires maynot have exactly equal and opposite voltages. For example, one wire mayhave −2 volts and the other wire may have +3 volts. Although there isstill a net difference across the pair of wires of +5 volts (which may,for example, correspond to a logic “1”), such a voltage imbalance willgenerate a current imbalance. Conventional technology uses isolatingmagnetic devices to deal with such imbalances. However, prior artmagnetic devices cannot physically handle the magnetizing force whichmay be induced by imbalanced DC current having a power complying withthe power requirements of new standards. If the transformer is notcapable of handling such imbalances, the transformer may saturate anddata may not transmit from one side of the transformer to the others Forexample, prior art transformers are able to handle low tolerances suchas 8 mA of DC current bias and the corresponding power such currentproduces. Now, industry standards are requiring that isolating magneticshandle 24 mA and as much as 34 mA of DC current bias. For example, theIEEE 802.3 AN standard requires such current bias tolerance. Prior atransformers are generally not capable of handling such currents andpower.

As an illustrative example, referring to FIG. 1, there is shown atransformer 40 in accordance with the prior art. Transformer 40 may beused as an isolating magnetic device. Transformer 40 is formed bywinding wires 44, 46, 48 and 50 around a toroid shaped core 42 formed ofa conductive material. Core 42 has a substantially circularcross-section. Wires 44, 46, 48 and 50 are evenly wound around core 42except in a gap area 38. As discussed above, when a high power DCcurrent bias is added onto an alternating current and applied to oneside of transformer 40, the entire core of transformer 40 may becomesaturated from the induced magnetic flux. Such saturation inhibitstransfer of data in the alternating rent component. Some attempts tocompensate for this problem in the prior art include using a larger core42. However, use of a larger core is not practical in many applicationsincluding connector applications due to space limitations.

Therefore, there is a need in the an for an electric device which canhandle higher power DC current bias than transformers available in theprior art and a method for manufacturing such a device.

SUMMARY OF THE INVENTION

One aspect of the invention is a method for producing an electricdevice. The method comprises inserting at least a first wire through afirst hole in a core and wrapping the first wire around a first side ofthe core. The method further comprises inserting at least a second wirethrough a second hole in the core, the second hole being spaced from thefirst hole and having a long axis extending substantially parallel to along axis of the first hole; and wrapping the second wire around asecond side of the core, the second side being spaced from the firstside.

Another aspect of the invention is an electrical device produced by amethod of inserting at least a first wire through a first hole in a coreand wrapping the first wire around a first side of the core. The methodfurther comprises inserting at least a second wire through a second holein the core, the second hole being spaced from the first hole and havinga long axis extending substantially parallel to a long axis of the firsthole; and wrapping the second wire around a second side of the core, thesecond side being spaced from the first side.

Yet another aspect of the invention is a connector for enablingelectrical communication with a plug. The connector comprises a set ofcontacts and a filter circuit in communication with the set of contacts.The connector further comprises a set of terminals in communication withthe filter circuit; wherein the filter circuit includes a transformerwith a core. The transformer is produced by the steps of inserting atleast a first wire through a first hole in the core and wrapping thefirst wire around a first side of the core. The transformer is furtherproduced by inserting at least a second wire through a second hole inthe core, the second hole being spaced from the first hole and having along axis extending substantially parallel to a long axis of the firsthole. The transformer is further produced by wrapping the second wirearound a second side of the core, the second side being spaced from thefirst side.

Another aspect of the invention is a method for producing an electricaldevice. The method comprises wrapping a first and second wire around afirst core and inserting the first and second wire and a third and afourth wire through a first hole in a second core. The method furthercomprises wrapping the first, second, third and fourth wires around afirst side of the second core and inserting fifth, sixth, seventh andeighth wires through a second hole in the second core, the second holebeing spaced from the first hole and having a long axis extendingsubstantially parallel to a long axis of the first hole. The methodfurther comprises wrapping the fifth, sixth, seventh and eighth wiresaround a second side of the second core, the second side being spacedfrom the first side; and wrapping the fifth and sixth wires around thefirst core.

Yet another aspect of the invention is a connector for enablingelectrical communication with a plug. The connector comprises a set ofcontacts and a filter circuit in communication with the set of contacts.The connector further comprises a set of terminals in communication withthe filter circuit. The filter circuit is produced by the steps ofwrapping a first and second wire around a first core and inserting thefirst and second Wire and a third and a fourth wire through a first holein a second core. The filter circuit is further produced by the steps ofwrapping the first, second, third and fourth wires around a first sideof the second core and inserting fifth, sixth, seventh and eighth wiresthrough a second hole in the second core, the second hole being spacedfrom the first hole and having a long axis extending substantiallyparallel to a long axis of the first hole. The filter circuit is fartherproduced by the steps of wrapping the fifth, sixth, seventh and eighthwires around a second side of the second core, the second side beingspaced from the first side; and wrapping the fifth and sixth wiresaround the first core.

Yet another aspect of the invention is an electrical device comprising abody having first and second holes extending therethough, the holesbeing spaced from one another and having longitudinal axes extendingsubstantially parallel to one another. The electrical device furthercomprises at least one wire extending through the first hole, the wirewrapped around a first side of the body and at least a second wireextending through the second hole in the body and wrapped around asecond side of the body, the second side being spaced from the firstside.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the present invention and many of theattendant features and advantages thereof will be readily understood byreference to the following detailed description when taken inconjunction with the accompanying drawings in which:

FIG. 1 is front view of a transformer in accordance with the prior art;

FIG. 2 is a side view of a core for use in accordance with an embodimentof the invention;

FIGS. 3A, 3B and 3C illustrate steps of winding wires around a core ofthe type shown in FIG. 2 in accordance with an embodiment of theinvention;

FIG. 4 is a top view of an electric device constructed in accordancewith an embodiment of the invention;

FIG. 5 is a top view of an electric device and a common mode chokeconstructed in accordance with an embodiment of the invention;

FIG. 6 is a diagram of a circuit which incorporates an electric devicein accordance with an embodiment of the invention;

FIG. 7 is a diagram of a circuit and corresponding tolerances of circuitdevices including an electric device in accordance with an embodiment ofthe invention; and

FIG. 8 is a diagram of a circuit and corresponding tolerances of circuitdevices including an electric device in accordance with an embodiment ofthe invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

Referring now to the drawings wherein like reference numerals describeidentical or corresponding parts throughout the several views, and moreparticularly to FIGS. 2 and 3A-3C, a core 50 resembles an ellipsoid withits ends cut off and with a substantially racetrack shapedcross-section. Core 50 may be made of a MgZn material with apermeability of 5000. As shown in FIG. 2, core 50 includes a first hole52 and a second hole 54 spaced from first hole 52. Magnetic flux lines56 which are set up in the core during operation are also schematicallyshown and will become clearer upon further discussion. Core 50 has afirst side 50 a and a second side 50 b. Referring to FIG. 3A, in orderto manufacture an electric device in accordance with an embodiment ofthe invention, four wires 60, 62, 64 and 66 are wrapped around core 50.Clearly, four wires are shown simply as an example and any number ofwires may be used. Wires 60, 62, 64 and 66 are inserted through hole 52of core 50. Wires 60, 62, 64 and 66 are then wrapped around first side50 a of core 50. Wires 60, 62, 64 and 66 are then inserted through hole52 again and wrapped around side 50 a again for a desired number ofturns. For example, X turns may be used. Once wires 60, 62, 64 and 66have been wrapped through hole 52 and around side 50 a of core 50, Xnumber of turns, the wires are extended across either a top or bottom ofcore 50 for insertion into hole 54—as shown in FIG. 3B. Alternatively, asecond set of wires (not explicitly shown) may be used for insertioninto hole 54. The top and bottom of core 50 may be identical and soeffectively both a top and bottom view are shown.

Referring to FIG. 3C, wires 60, 62, 64 and 66 (or a second set of wires)are then inserted through hole 54 of core 50 and then wrapped aroundsecond end 50 b of core 50. The wires are inserted through hole 54 andwrapped around second end 50 b the desired number of turns—for example,X turns. Dot notation is used to assist an assemblyman in performing thewindings—where the dots indicate starting points for the wires. As shownin FIGS. 3C and 4, after the wires have been wrapped through hole 52,around first side 50 a, through hole 54 and around second side 50 b, anelectric device 70 in accordance with the invention is realized. Again,the extension of the wires over the top/bottom of core 50 need not beperformed, if two sets of wires are used.

If desired, device 70 may be combined with a conventional common modechoke 72 as shown in FIG. 5. To form this combination, wires 62 and 66are first wound around a toroid 74 having a substantially circularcross-section. Wires 62 and 66 (shown as being green and blue in color,respectively) are joined with wires 60 and 64 (red and natural) andwrapped through hole 52 and first side 50 a. Wires 60, 62, 64 and 66 arethen extended over a top or bottom of core 70 (except in situationswhere two sets of wires are used) and then wrapped through hole 54 andsecond side 50 b. Wires 60, 64 remain on a left side of core 70 whilewires 62 and 66 are wound again around toroid 74.

Referring to FIG. 6, there is shown a circuit 80 which may use device70. As shown, circuit 80 is a representation of the combination ofdevice 70 and common mode choke 72 illustrated in FIG. 5. Referringmomentarily, to FIG. 2, in electric device 70, magnetic flux linesoccurring in a central portion of the device extend in opposingdirections. Conversely, magnetic flux lines towards distal ends of thedevice 70, extend in only a single direction. If such flux lines have ahigh enough intensity, such as may be provided by high power DC currentbias, the flux may indeed saturate those portions of the device.However, as the flux lines in the central portion of the device maycancel each other out, saturation does not occur in the central portionand data transfer may still occur in that area.

Referring to FIG. 7 there is shown another circuit diagram 96 which mayuse an electric device in accordance with an embodiment of theinvention. Circuit 96 may be used in a connector. As shown, contacts 92may be used in the connector to communicate with an inserted plug (notshown). A termination circuit 94 may be used to balance a load of wiresin said plug. Device 70 may be used as the load for the terminals of theplug. Choke 72 may be utilized to minimize the presence of common modecurrents. As shown, optional LEDs 96 may be used. As discussed, device70 allows data to be transmitted therethrough even in the presence ofhigh power DC current bias and corresponding induced magnetic fields.Some tolerances which may be used for the circuit elements are shown.

Referring to FIG. 8, another circuit diagram 100 is shown which maybeused in accordance with an embodiment of the invention. As with thecircuit shown in FIG. 7, circuit 100 includes terminals 92, filtercircuit 94, device 70 and choke 72. In circuit I 00, four sets ofdevices 70 an chokes 72 are shown.

Thus, by implementing a new winding method, a new electric device may berealized which can handle higher power currents and magnetizing forceswhich would saturate devices of the prior art As discussed, any numberof turns may be used for each of the windings. The number of turns maybe based on a desired return loss parameter. Moreover, although fourwires are shown, clearly any number of wire may be used.

In the prior art devices, high power DC currents create a magnetic fluxwhich may saturate the entire transformer. As a consequence, AC datacannot pass through the transformer because there is no magnetizingforce available. In contrast, in the invention, the center of theelectric device does not necessarily saturate and so data may passtherethrough. Moreover, higher power and corresponding inducedmagnetizing force can be handled and the device may comply with currentIEEE standards. Furthermore, in the prior art, some attempts to dealwith these issues include use of a larger transformer. In contrast, acore with the size of, for example, ¼ inch by ¼ inch by ⅛ of an inch maybe used in the invention. In the prior art, a toroid of twice that sizemay be required. An electric device in accordance with the invention maybe backward compatible and may also be used in low power applications.

While preferred embodiments of the invention have described, the scopeof the invention is only limited by the claims.

1. A method for producing an electric device, the method comprising:inserting at least a first wire through a first hole in a core; wrappingthe first wire around a first side of the core; inserting at least asecond wire through a second hole in the core, the second hole beingspaced from the first hole and having a long axis extendingsubstantially parallel to a long axis of the first hole; and wrappingthe second wire around a second side of the core, the second side beingspaced from the first side.
 2. The method as recited in claim 1, whereinthe first and second wires each comprise four wires.
 3. The method asrecited in claim 1, further comprising: performing both steps ofinserting and both steps of wrapping a defined number of times.
 4. Themethod as recited in claim 1, wherein the core is substantially acut-off ellipsoid.
 5. The method as recited in claim 1, wherein the corehas substantially a racetrack cross-section.
 6. The method as recited inclaim 1, wherein the first and second wires are part: of a single wireand the method further comprises extending the first wire over a top orbottom of the core after the wrapping the first wire around the firstside of the core.
 7. An electrical device produced by a method of:inserting at least a first wire through a first hole in a core; wrappingthe first wire around a first side of the core; inserting at least asecond wire through a second hole in the core, the second hole beingspaced from the first hole and having a long axis extendingsubstantially parallel to -a long axis of the first hole; and wrappingthe second wire around a second side of the core, the second side beingspaced from the first side.
 8. The method as recited in claim 7, whereinthe first and second wires are part of a single wire and the methodfurther comprises extending the first wire over a top or bottom of thecore after the wrapping the first wire around the first side of thecore.
 9. A connector for enabling electrical communication with a plug,the connector comprising: a set of contacts; a filter circuit incommunication with the set of contacts; and a set of terminals incommunication with the filter circuit, wherein the filter circuitincludes a transformer with a core, the transformer produced by thesteps of: inserting at least a first wire through a first hole in thecore; wrapping the first wire around a first side of the core; insertingat least a second wire through a second hole in the core, the secondhole being spaced from the first hole and having a long axis extendingsubstantially parallel to a long axis of the first hole; and wrappingthe second wire around a second side of the core, the second side beingspaced from the first side.
 10. The connector as recited in claim 9,wherein the core is substantially a cut-off ellipsoid.
 11. The method asrecited in claim 9, wherein the first and second wires are part of asingle wire and the method further comprises extending the first wireover a top or bottom of the core after the wrapping the first wirearound the first side of the core.
 12. A method for producing anelectrical device, the method comprising: wrapping a &a and second wirearound a first core; inserting the first and second wire and a third anda fourth wire through a first hole in a second core; wrapping the first,second, third and fourth wires around a first side of tie second core;inserting fifth, sixth, seventh and eighth wires through a second holein the second core, the second hole being spaced from the first hole andhaving a long axis extending substantially parallel to a long axis ofthe first hole; wrapping the fifth, sixth, seventh and eighth wiresaround a second side of the second core, the second side being spacedfrom the first side; and wrapping the fifth and sixth wires around thefirst core.
 13. The method as recited in claim 12, wherein the firstcore is a toroid.
 14. The method as recited in claim 12, wherein thesecond core is substantially a cut-off ellipsoid.
 15. The method asrecited in claim 12, wherein the first and fifth wires are part of asingle wire, the second and sixth wires are part of a single wire, thethird and seventh wires are part of a single wire, the fourth and eighthwires are part of a single wire, and the method further comprisesextending the first, second, third and fourth wires over a top or bottomof the second core after the wrapping the first, second, third andfourth wires around the first side of the second core.
 16. A connectorfor enabling electrical communication with a plug, the connectorcomprising: a set of contacts; a filter circuit in communication withthe set of contacts; and a set of terminals in communication with thefilter circuit;, wherein the filter circuit is produced by the steps of:wrapping a first and second wire around a first core; inserting thefirst and second wire and a third and a fourth wire through a first holein a second core; wrapping the first, second, third and fourth wiresaround a first side of the second core; inserting fifth, sixth, seventhand eighth wires through a second hole in the second core, the secondhole being spaced from the first hole and having a long axis extendingsubstantially parallel to a long axis of the first hole; wrapping thefifth, sixth, seventh and eighth wires around a second side of thesecond core, the second side being spaced from the first side; andwrapping the fifth and sixth wires around the first core.
 17. Theconnector as recited in claim 16, wherein the first and fifth wires arepart of a single wire, the second and sixth wires are part of a singlewire, the third and seventh wires are part of a single wire, the fourthand eighth wires are part of a single wire, and wherein the filtercircuit is further produced by extending the first, second, third andfourth wires over a top or bottom of the second core after the wrappingthe first, second, third and fourth wires around the first side of thesecond core.
 18. An electrical device comprising: a body having firstand second holes extending therethough, the holes being spaced from oneanother and having longitudinal axes extending substantially parallel toone another; at least one wire extending through the first hole, thewire wrapped around a first side of the body; at least a second wireextending through the second hole in the body and wrapped around asecond side of the body, the second side being spaced from the firstside.